diff --git a/src/parse/macros.rs b/src/parse/macros.rs
index 6a1ea04..beb47cf 100644
--- a/src/parse/macros.rs
+++ b/src/parse/macros.rs
@@ -17,8 +17,8 @@ macro_rules! wrap_attributes {
             }
         }
 
-        #[cfg(test)]
         impl $ident {
+            #[allow(dead_code)]
             pub(crate) fn append(&mut self, attr: Attribute) {
                 self.inner.attributes.push(attr)
             }
diff --git a/src/render/fixture.rs b/src/render/fixture.rs
index 52c9d36..30cae35 100644
--- a/src/render/fixture.rs
+++ b/src/render/fixture.rs
@@ -17,10 +17,18 @@ fn wrap_return_type_as_static_ref(rt: ReturnType) -> ReturnType {
     }
 }
 
-fn output_type(rt: &ReturnType) -> syn::Type {
+fn wrap_call_impl_with_call_once_impl(call_impl: TokenStream, rt: &ReturnType) -> TokenStream {
     match rt {
-        syn::ReturnType::Type(_, t) => *t.clone(),
-        _o => parse_quote! { () },
+        syn::ReturnType::Type(_, t) => parse_quote! {
+            static mut S: Option<#t> = None;
+            static CELL: std::sync::Once = std::sync::Once::new();
+            CELL.call_once(|| unsafe { S = Some(#call_impl) });
+            unsafe { S.as_ref().unwrap() }
+        },
+        _ => parse_quote! {
+            static CELL: std::sync::Once = std::sync::Once::new();
+            CELL.call_once(|| #call_impl );
+        },
     }
 }
 
@@ -59,13 +67,7 @@ pub(crate) fn render(fixture: ItemFn, info: FixtureInfo) -> TokenStream {
     let mut call_impl = render_exec_call(parse_quote! { #name }, args, asyncness.is_some());
 
     if info.attributes.is_once() {
-        let return_type = output_type(&output);
-        call_impl = parse_quote! {
-            static mut S: Option<#return_type> = None;
-            static CELL: std::sync::Once = std::sync::Once::new();
-            CELL.call_once(|| unsafe { S = Some(#call_impl) });
-            unsafe { S.as_ref().unwrap() }
-        };
+        call_impl = wrap_call_impl_with_call_once_impl(call_impl, &output);
         output = wrap_return_type_as_static_ref(output);
         default_output = wrap_return_type_as_static_ref(default_output);
     }
@@ -147,7 +149,6 @@ mod should {
 
     use super::*;
     use crate::test::{assert_eq, *};
-    use mytest::*;
     use rstest_reuse::*;
 
     #[derive(Clone)]
diff --git a/tests/fixture/mod.rs b/tests/fixture/mod.rs
index e14078e..1cb0517 100644
--- a/tests/fixture/mod.rs
+++ b/tests/fixture/mod.rs
@@ -198,9 +198,11 @@ mod should {
             .assert(output);
     }
 
-    #[test]
-    fn accept_once_attribute_and_call_fixture_just_once() {
-        let project = prj("once.rs").with_nocapture();
+    #[rstest]
+    #[case("once.rs")]
+    #[case::no_return("once_no_return.rs")]
+    fn accept_once_attribute_and_call_fixture_just_once(#[case] fname: &str) {
+        let project = prj(fname).with_nocapture();
 
         let output = project.run_tests().unwrap();
 
diff --git a/tests/resources/fixture/once_no_return.rs b/tests/resources/fixture/once_no_return.rs
new file mode 100644
index 0000000..26674c9
--- /dev/null
+++ b/tests/resources/fixture/once_no_return.rs
@@ -0,0 +1,20 @@
+use rstest::*;
+
+#[fixture]
+#[once]
+fn once_fixture() {
+    eprintln!("Exec fixture() just once");
+}
+
+#[rstest]
+fn base(_once_fixture: ()) {
+    assert!(true);
+}
+
+#[rstest]
+#[case()]
+#[case()]
+#[case()]
+fn cases(_once_fixture: ()) {
+    assert!(true);
+}